This invention relates to an electronic coin selection device employing coils for discriminating true coins from false or counterfeit coins.
Important problems to be solved in an electronic coin selection device employing coils are:
(1) How to improve accuracy in detection by the coils; and PA1 (2) How to ensure sorting of a coin to be accepted and a coin to be returned.
In prior art electronic coin selection devices employing coils, a coin discrimination output is obtained by detecting and amplifying an output of a receiving coil and then comparing this output with a reference voltage. Irregularity however occurs in the output of a detection and amplification circuit due to variation in the amplification characteristic caused by change in temperature of the circuit, errors in assembling of the circuit, variation in power voltage for an oscillation source and other causes. This irregularity adversely affects the accuracy in discrimination of coins by the coin selection device.
Sorting of coins into coins to be accepted and coins to be returned is effected at a coin sorting point in response to the coin discrimination output of the detection and amplification circuit. An erroneous operation in the sorting of coins tends to take place in a case where true coins and false coins are deposited in succession at extremely short intervals. If true coins and false coins are deposited in the coin slot in rapid succession, true coins and false coins must be sorted out in extremely short time frames. This causes an error in timing, resulting in erroneous operation such that a false coin is accepted and a true coin is returned.